1. Field of the Invention
This invention relates to digital coding of audio signals and, more particularly, to an improved wideband coding technique suitable, for example, for audio signals which include a mixture of music and speech.
2. Background Description
The need for low bitrate and low delay audio coding, such as is required for video conferencing over modern digital data communications networks, has required the development of new and more efficient schemes for audio signal coding.
However, the differing characteristics of the various types of audio signals has the consequence that different types of coding techniques are more or less suited to certain types of signals. For example, transform coding is one of the best known techniques for high quality audio signal coding in low bitrates. On the other hand, speech signals are better handled by model-based CELP coders, in particular for the low delay case, where the coding gain is low due to the need to use a short transform.